DE60034831T2 - Method and base station for transmitting information via a common packet data channel - Google Patents

Description

BACKGROUND OF THE INVENTION

These This invention relates to spread spectrum communications, and more particularly said on code division multiple access (CDMA) cellular packet switching systems.

DESCRIPTION TO THE STATE OF TECHNOLOGY

Youngest is as a standard, a random-access burst architecture proposed, which preamble a preamble, followed by a data section. The signal preamble has 16 symbols, where the preamble sequence is replaced by a orthogonal gold code is scattered. A remote station attained a chip and frame synchronization, but no consideration in terms of a closed-loop power control or given a collision detection.

The document US-A-5,841,768 describes a method and system for transmitting data for one of a plurality of wireless remote station (RS) handsets through a base station (BS) of a wireless telecommunications network, the base station of a BS spread spectrum transmitter and a BS spread spectrum receiver, the method comprising Steps contains:
Transmitting a frame timing signal from the spread spectrum BS receiver over a common synchronization broadcast channel having a common chip sequence signal;
Receiving the common-synchronization broadcasting channel containing a frame timing signal on an RS spread-spectrum receiver of the one RS;
Determining a frame timing on an RS spread spectrum receiver from the one RS for the received frame timing signal;
Transmitting an access burst signal from an RS spread spectrum transmitter from the one RS handset, the access burst signal including access codes or short codes which transmit them at sequentially increasing power levels;
Receiving at least one code of the access burst signal at the BS spread-spectrum receiver at a detected power level;
Sending an acknowledgment from the BS spread spectrum transmitter in response to receipt of the code of the access burst signal; Receiving the acknowledgment at the RS spread spectrum receiver;
Receiving the acknowledgment at the RS spread spectrum receiver and stopping the transmission of the access burst in response thereto; and
Transmitting a spread spectrum signal comprising any one of data and power control information from the RS spread spectrum transmitter in response to receipt of the acknowledgment.

Outline of the invention

A general object of the invention is an effective method for Packet data transfer on CDMA systems.

A Another object of the invention is a high data throughput and a low delay and an effective power control.

These Tasks are achieved by a method according to claim 1, a base station according to claim 6 and a processing unit according to claim 11 solved.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated and a part of the description, represent preferred embodiments of the invention, and together with the description serve to explain the principles of the invention.

1 Fig. 10 is a general packet channel system block diagram with a common control downlink channel;

2 Fig. 10 is a general packet channel system block diagram with an assigned downlink channel;

3 Fig. 10 is a block diagram of a base station receiver and transmitter for a common packet channel;

4 Fig. 10 is a block diagram of a remote station receiver and transmitter for a common packet channel;

5 is a timing diagram for an access burst transmission;

6 provides an access burst for a common packet channel of 5 using a common control downlink channel;

7 provides access to a common packet channel from 5 using an assigned downlink channel;

8th shows the structure of the preamble;

9 represents header and pilot formats;

10 Fig. 11 is a timing chart and a frame format of a common packet channel of the common control route from the downlink;

11 represents a frame format of packet data of a common packet channel;

12 FIG. 12 illustrates a timing diagram of a common packet channel for mutual front-end transmit power control; FIG.

13 Fig. 12 illustrates a timing diagram of a common packet channel with an associated assigned physical channel in the downlink;

14 Fig. 12 illustrates a timing diagram of a common packet channel with an associated physical channel in the downlink;

15 Fig. 12 illustrates a timing diagram of a common packet channel with an associated physical channel in the downlink; and

16 FIG. 10 illustrates a timing diagram of a common packet channel with an associated dedicated downlink physical channel having a common preamble for two or more base stations. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It will now be detailed to the presently preferred embodiments of the invention, examples of which are shown in the accompanying drawings are shown, in which like reference numerals on the Show the same elements across multiple views.

Of the common packet channel is a new and novel uplink transport channel for transmission of variable size packages of one Remote station to a base station within a transmission area without the need for a two-way route with any or to obtain a set of base stations. The channel resource allocation is based on competition; that is, a number of remote stations at any time for the same resources can be satisfactory, as found in the ALOHA system.

In the in 1 A common packet channel provides an enhancement to a code division multiple access (CDMA) system using spread spectrum modulation. The CDMA system has a plurality of base stations (BS) 31 . 32 . 33 , and a plurality of remote stations (RS). Every remote station 35 has an RS spread spectrum transmitter and a RS spread spectrum receiver. An uplink goes from the remote station 35 to a base station 31 , The uplink has the common packet channel (CPCH). A downlink goes from a base station 31 to the remote station 35 and is referred to as a common control channel (CCCH). The common control channel has a common signaling used by the plurality of remote stations.

An alternative to the common control channel, which still uses the common packet channel, is the assigned physical channel in the downlink (DPCH), which is in 2 is shown. The assigned downlink channel has signaling used to control a single remote station.

As exemplified in 3 A BS spread spectrum transmitter and a BS spread spectrum receiver are shown. The BS spread spectrum transmitter and the BS spread spectrum receiver are located at the base station 31 , The BS spread spectrum receiver includes an antenna 309 , which to a disseminator 310 coupled to a receiver radio frequency (RF) section 311 , a local oscillator 313 , a quadrature demodulator 312 and an analog-to-digital converter 314 , The receiver RF section 311 is between the disseminator 310 and the quadrature demodulator 312 coupled. The quadrature demodulator is at the local oscillator 313 and the analog-to-digital converter 314 coupled. The output of the analog-to-digital converter 314 is to a programmable adaptation filter 315 coupled.

A preamble processor 316 , Pilot processor 317 and data and control processor 318 are to the programmable adaptation filter 315 coupled. A controller 319 is at the preamble processor 316 , Pilot processor 317 and data and control processor 318 coupled. A deinterleaver 320 is between the controller 319 and a forward error correction decoder (FEC) 321 coupled.

The BS spread spectrum transmitter includes a forward error correction (FEC) encoder 322 which is connected to an interleaver 323 is coupled. A packet formatter 324 is to the interleaver 323 and to the controller 319 coupled. A device with variable gain 325 is between the packet formatter 324 and a product device 326 coupled. A scattering sequence generator 327 is to the product device 326 coupled. A digital-to-analog converter 328 is between the product device 328 and the quadrature modula gate 329 coupled. The quadrature modulator 329 is to the local oscillator 313 and to a transmitter RF section 330 coupled. The transmitter RF section 330 is to the disseminator 310 coupled.

The control 319 has control paths connected to the analog-to-digital converter 314 , the programmable adjustment filter 315 , the preamble processor 316 , the digital-to-analog converter 328 , the spreading sequence generator 327 , the variable gain device 325 , the packet formatter 324 , the de-interleaver 320 , the FEC decoder 321 , the interleaver 323 and the FEC encoder 322 are coupled.

A received spread spectrum signal from the antenna 309 happens through the disseminator 310 and gets through the receiver RF section 311 reinforced and filtered. The local oscillator 313 generates a local signal, which is the quadrature demodulator 312 used to demodulate in-phase and quadrature-phase components of the received spread-spectrum signal. The analog-to-digital converter 314 converts the in-phase component and the quadrature-phase component into a digital signal. These functions are known in the art, and variations on this block diagram can accomplish the same function.

The programmable adaptation filter 315 the received spread spectrum signal is scattered. A correlator may be used as an alternative as an equivalent means for diffusing the received spread spectrum signal.

The preamble processor 316 detects the preamble portion of the received spread spectrum signal. The pilot processor detects and synchronizes to the pilot portion of the received spread spectrum signal. The data and control processor detects and processes the data portion of the received spread spectrum signal. Captured data passes through the controller 319 to the deinterleaver 320 and FEC decoder 321 , There will be data and signaling from the FEC decoder 321 output.

The BS transmitter transmits data through the FEC encoder 322 FEC-encoded and through the interleaver 321 nested. The packet formatter formats data, signaling, an acknowledgment signal, a collision detection signal, a pilot signal, and a transmission power control (TPC) signal in a packet. The packet is output from the packet formatter and the packet level is passed through the variable gain device 325 strengthened or subdued. The package will go through the product device 326 with a Streuchipsequenz from the scattering sequence generator 327 processed in the spread spectrum. The package is powered by the digital-to-analog converter 328 converted into an analog signal, and there are in-phase and quadrature-phase components through the quadrature modulator 329 using a signal from the local oscillator 313 generated. The packet is transmitted by the transmitter RF section 330 converted to a carrier frequency, filtered and amplified, and then passes through the propagator 310 and is through the antenna 309 broadcast.

In the in 4 In the illustrative embodiment shown, an RS spread spectrum transmitter and an RS spread spectrum receiver are shown. The RS spread spectrum transmitter and the RS spread spectrum receiver are located at the remote station 35 , what a 1 is shown. The RS spread spectrum receiver includes an antenna 409 , which to a disseminator 410 coupled, a receiver radio frequency (RF) section 411 , a local oscillator 413 , a quadrature demodulator 412 and an analog-to-digital converter 414 , The receiver RF section 411 is between the disseminator 410 and the quadrature demodulator 412 coupled. The quadrature demodulator is connected to the local oscillator 413 and the analog-to-digital converter 414 coupled. The output of the analog-to-digital converter 415 is to a programmable adaptation filter 415 coupled.

A receipt acknowledgment detector 416 , a pilot processor 417 and a data and control processor 418 are to the programmable adaptation filter 415 coupled. A controller 419 is to the receipt confirmation detector 416 , Pilot processor 417 and data and control processor 418 coupled. A deinterleaver 420 is between the controller 419 and a forward error correction decoder (FEC) 421 coupled.

The RS spread spectrum transmitter includes an encoder 422 for forward error correction (FEC) 422 which is connected to an interleaver 423 is coupled. A packet formatter 424 is via a multiplexer 451 to the interleaver 423 and to the controller 419 coupled. A preamble generator 452 and a pilot generator 453 for the preamble are to the multiplexer 451 coupled. A device with variable gain 425 is between the packet formatter 424 and a product device 426 coupled. A spreading sequence generator 427 is at the product device 426 coupled. A digital-to-analog converter 428 is between the product device 428 and a quadrature modulator 429 coupled. The quadrature modulator 429 is to the local oscillator 413 and a transmitter RF section 430 coupled. The transmitter RF section 430 is to the disseminator 410 coupled.

The control 419 has tax breaks, wel to the analog-to-digital converter 414 , the programmable adjustment filter 415 , the acknowledgment of receipt 416 , the digital-to-analog converter 428 , the scattering sequence generator 427 , the variable gain device 425 , the packet formatter 425 , the de-interleaver 420 , the FEC decoder 421 , the interleaver 423 , the FEC encoder 422 , the preamble generator 452 and the pilot generator 453 are coupled.

A received spread spectrum signal from the antenna 409 happens through the disseminator 410 and gets through the receiver RF section 411 reinforced and filtered. The local oscillator 413 generates a local signal, which is the quadrature demodulator 412 used to demodulate in-phase and quadrature-phase components of the received spread-spectrum signal. The analog-to-digital converter 414 converts the in-phase component and the quadrature-phase component into a digital signal. These functions are known in the art, and variations on this block diagram can accomplish the same function.

The programmable adaptation filter 415 the received spread spectrum signal is scattered. A correlator may be used as an alternative as an equivalent means for diffusing the received spread spectrum signal.

The receipt confirmation detector 416 detects the acknowledgment in the received spread spectrum signal. The pilot processor detects and synchronizes to the pilot portion of the received spread spectrum signal. The data and control processor detects and processes the data portion of the received spread spectrum signal. Captured data passes through the controller 419 to the deinterleaver 420 and FEC decoder 421 , There will be data and signaling from the FEC decoder 421 output.

The RS transmitter transmits data through the FEC encoder 422 FEC-encoded and through the interleaver 423 nested. The preamble generator 452 generates a preamble, and the pilot generator 453 creates a pilot for the preamble. The multiplexer 451 multiplexes the data, the preamble and the pilot, and the packet formatter 424 formats the preamble, the pilot and the data in a packet of a common packet channel. Further, the packet formatter formats the data, the signaling, the acknowledgment signal, the collision detection signal, the pilot signal, and the TPC signal into one packet. The packet is output from the packet formatter, and the packet level is passed through the variable gain device 425 strengthened or subdued. The package will go through the product device 426 with a Streuchipsequenz from the scattering sequence generator 427 processed in the spread spectrum. The package is powered by the digital-to-analog converter 428 converted to an analog signal, and there are in-phase and quadrature-phase components through the quadrature modulator 429 using a signal from the local oscillator 413 generated.

Referring to 5 the base station transmits a common synchronization channel having a frame period TF. The common synchronization channel has a common chip sequence signal common to the plurality of remote stations communicating with the particular base station. In a particular embodiment, the time TF of one frame is equal to 10 milliseconds. Within a frame there are eight access slots. Each access slot lasts for 1.25 milliseconds. A timing for the access slots is the frame timing, and the portion of the common synchronization channel with the frame timing is referred to as the frame timing signal. The frame timing signal is the timing used by a remote station in selecting an access slot in which an access burst signal is to be transmitted.

A first remote station trying to access the base station, has a first RS spread spectrum receiver for receiving the common Synchronization channel, which is sent by the base station becomes. The first RS spread spectrum receiver determines a frame timing from the frame timing signal.

A first RS spread spectrum transmitter located at the first remote station transmits an access burst signal. An access burst signal, as in 5 shown starts at the beginning of an access slot as determined by the frame timing section of the common synchronization channel.

6 Illustratively illustrates the access burst format of the common packet channel for each access burst signal. Each access burst signal has a plurality of segments. Each segment has a preamble followed by a pilot signal. The plurality of segments each have a plurality of power levels. More specifically, the power level of each segment increases with each subsequent segment. Thus, a first segment has a first preamble and a pilot at a first power level P ₀ . A second segment has a second preamble and a second pilot at a second power level P ₁ . The third segment has a third preamble and a third pilot at a third power level P ₂ . The first preamble, the second preamble, the third preamble, and subsequent preambles may be identical or different. The power level of the pilot is preferably less than the power level of the preamble. A preamble serves for synchronization and a corresponding pilot following a preamble serves to maintain the spread spectrum BS receiver on receipt of the spread spectrum signal from the remote station once a preamble is detected.

A subsequent increase or decrease in power levels is basically a process-coupled power control system. Once a BS spread spectrum receiver Detected preamble from the remote station, sends the BS spread spectrum transmitter an acknowledgment (ACK) signal.

Referring to 4 the preamble is signaled by the preamble generator 452 generated, and the pilot is through the pilot generator 453 generated. A preamble format is in 8th shown. The preamble format with a pilot is in 9 shown. The multiplexer 451 dials with a clock from the controller 419 the preamble, then a corresponding pilot for the packet formatter 424 out. A sequence of preambles and pilots may be generated and as part of the packet by the packet formatter 424 to be created. The preambles and pilots can adjust their power levels either in the preamble generator 452 and pilot generator 453 or by the variable gain device 425 have set.

The BS spread-spectrum receiver receives the access burst signal at a detected power level. More specifically, the access burst signal has the plurality of preambles each at a plurality of power levels. If a preamble having a sufficient power level is detected at the BS spread-spectrum receiver, then an acknowledgment (ACK) signal is sent from the BS spread-spectrum transmitter. The ACK signal is in 6 shown in response to the fourth preamble having sufficient power for detection by the BS spread-spectrum receiver.

3 shows the preamble processor 316 for detecting the preamble and the pilot processor 317 to continue receiving the packet after detecting the preamble. Upon detection of the preamble, the processor initiates 319 an ACK signal which becomes the packet formatter 324 and emitted by the BS spread spectrum transmitter.

The first RS spread spectrum receiver receives the acknowledgment signal. Upon receiving the ACK signal, the first RS spread spectrum transmitter transmits to the BS spread spectrum receiver a spread spectrum signal having data. The data is in 6 at a time after the ACK signal shown. The data includes a collision detection (CD) portion of the signal, referred to herein as a collision detection signal, and a message.

In response to each packet sent from the RS spread spectrum transmitter, the BS receiver detects the collision detection portion of the data and retransmits the data field of the collision detection portion of the data to the remote station. 10 shows the timing diagram for retransmission of the collision detection field. There are several collision detection retransmission slots which can be used to retransmit the collision detection field for multiple remote stations. If the collision detection field is correctly retransmitted to the remote station, then the remote station will know that its packet has been successfully received by the base station. If the collision detection field is not retransmitted correctly by the base station, then the remote station assumes that there is a collision with a packet sent by another remote station and stops further transmission of the data.

11 shows a frame format of a data payload of a common packet channel.

In operation, an overview of the way this transport mechanism is used is as follows. A remote station (RS) looks for a power-on after transmission from nearby base stations. Upon successful synchronization with one or more base stations, the remote station receives the necessary system parameters from a broadcast control channel (BCCH) transmitted continuously through all base stations. Using the information sent by the BCCH, the remote station may determine various parameters required for a first transmission to a base station. Parameters of interest are the loading of all base stations in the vicinity of the remote station, their antenna characteristics, spreading codes used to spread the downlink transmitted information, the timing information, and other control information. With this information, the remote station can send specific waveforms to catch the attention of a nearby base station. In the common packet channel, the remote station, which has all the necessary information from the nearby base station, starts transmission of a particular one Preambles of a set of predetermined preambles, at properly selected time intervals. The particular structure of the preamble waveforms is selected on the basis that detection of the preamble waveform at the base station is as simple as possible with a minimum loss in detectability.

The Physical Common Packet Channel (CPCH) is used to transport the CPCH. It is based on the well-known slotted ALOHA approach. There are a number of well-defined time offsets relative to the frame boundary of a downlink received BCCH channel. These time offsets have access slots. The number of access slots is chosen according to the particular application available. As an example, as in 5 eight access slots are spaced 1.25 msec apart in a 10 msec frame.

According to 5 A remote station randomly selects an access slot and attempts to connect to a base station by sending a preamble waveform. The base station is capable of recognizing this preamble and awaits its receipt at the beginning of each access slot. The length of the access burst is variable, and it is allowed that the length of the access burst varies from a few access slots to many frame durations. The amount of data sent by the remote station may depend on several factors. Some of them are: a class capability of the remote station, a prioritization, the control information sent down by the base station, and various bandwidth management protocols present and executed at the base station. A field at the beginning of the data section denotes the length of the data.

The structure of the access kick is in 6 shown. The burst of access begins with a set of preambles of duration Tp whose power increases step by step from preamble to preamble. The transmitted power during each preamble is constant. For the duration T _D between preambles, the access burst contains a pilot signal which is transmitted at a fixed power level ratio in relation to the previously transmitted preamble. There is a clear match between the code structure of the preamble and the pilot signal. The pilot signal can be eliminated by setting it to a zero power level.

The transfer the preamble is terminated because either the preamble, detected by the base station, has been selected or the base station to the remote station with a shift-1 acknowledgment L1 ACK has replied which the remote station is also successful has received. A transmission of the preamble is also terminated when the remote station the maximum allowed number of preambles Mp sent Has. Upon receipt of this L1 ACK, the remote station begins transmission their data. Once the remote station more than Mp preambles has sent, undermines a forced random reset procedure. This procedure forces the remote station to transmit its access burst to a later one Delay time. The random Reset procedure can be based on the priority statues the remote station can be parameterized. The amount by which the power of preamble is increased to preamble, is Dp, which either for All cells are fixed at all times or repeatedly over the BCCH is sent out. Remote stations with different priority status can have one power increase which depends on a priority status, which assigned to the remote station. The priority status can either be predetermined or the remote station after a negotiation with the base station be assigned to.

The preamble signal structure

There is a large set of possible preamble waveforms. Each base station is assigned a subset of preambles from the set of all preamble waveforms in the system. The set of preambles using a base station is transmitted over its BCCH channel. There are many ways to generate header file waveforms. One existing way is to use a single orthogonal Gold code per preamble from the set of all possible orthogonal Gold codes of length L. A preamble may then be constructed by repeating the Gold code at a number N to a length N complex sequence to send. For example, if A denotes the orthogonal Gold code and G _i = {g _{i, 0} g _{i, 1} g _{i, 2} ... g _{i, N-1} } denotes a length N complex sequence, then a preamble can be formed , as in 8th where g _{i, j} j = 0, ..., N-1 multiply each element in A. Normally, the sets of G _i 's are chosen to be orthogonal to one another.

This becomes a maximum of N possible waveforms allow. The total number of possible Signal preambles is then L · N.

The preferred approach is to use different codes, rather than a single repeating code, in generating each preamble. In this case, if L possible codes, not necessarily Gold codes, are possible, which are marked A ₀ , A ₁ , ..., A _L-1 , then possible preambles will be as in 8th be shown. The order of the A _i 's may be chosen such that identical codes are not used at the same locations for two different preambles. A similar approach can be used to form the pilot signals.

The common downlink control channel

In 10 the construction of the common downlink control channel for even and odd slots is shown. The even-numbered slots contain reference data and control data. The pilot symbols are used to obtain a reference for demodulating the remaining control symbols. The control symbols are made up of Transport Frame Indicator (TFI) symbols, Power Control (PC) symbols, a Collision Detection (CD) symbol, and Signaling Symbols (SIG). The odd-numbered slots contain all information containing the even-numbered slots plus an acknowledgment of receipt (ACK) signal. Uneven slots do not contain collision detection fields.

Of the Uplink CPCH is over the last sent signal preamble is shown. After the last one sent start signal has the base station successfully the transfer of the last transmitted preamble, and transmits the acknowledgment signal back. During the same time, the remote station is tuned to that ACK signal to receive. The transmitted ACK signal corresponds to the specific preamble setup, which is on the uplink is sent. Once the remote station detects the ACK signal, which is the signal preamble sent by the remote station corresponds, the remote station starts transmission their data.

According to the preamble structure in the uplink, there is a coincidence in the time-power control information symbol and a coincidence in the time-collision detection field. At the start of a data transfer, the remote station uses the downlink power control information to adjust its transmitted power. The power control symbols are decoded to obtain binary decision data, which is then used to increase or decrease the transmitted power accordingly. 11 Fig. 10 shows the structure of the uplink frame and the slot format for the data portion of the uplink transmission. Data and control information is sent in an in-phase and quadrature-phase multiplex format. That is, the data portion on the in-phase coordinate and the control portion on the quadrature-phase coordinate can be transmitted. The modulation for the data and the control is BPSK. The control channel contains the information for the receiver to enable demodulation of the data. The control channel provides upper layer system functionality. The data section contains one or more frames. Each frame contains a number of slots. As one example, the frame duration may be 10 milliseconds long and the slot duration may be 0.625 milliseconds. In this case, there are 16 slots per frame. The beginning of the data payload contains a collision detection field which is used to relay information about the possibility of collision with other simultaneously transmitted remote stations. The collision detection field is read out by the base station. The base station awaits the presence of the collision detection field because it has provided an ACK signal at the last time slot.

The Contains collision detection field a temporary one Identification (ID) number randomly transmitted by the remote station for the transmission of the current package is. The base station reads out the collision detection field and reflects or transmits the collision detection field on the downlink back. If the collision detection field, by the remote station is recorded, agrees with that, which recently the same remote station was sent is the collision detection field then an identification about it, that the transmission is received correctly. The remote station then continues, the rest of the package. In the case of the collision detection field was not received correctly by the remote station the remote station then receives the packet through the base station as faulty and interrupts a transfer of the remaining Package.

The function of the remaining fields is as follows. The pilot field allows demodulation of both the data and control bits. The transmitted power control (TPC) bits are used to control the power of a corresponding downlink channel in a case where a downlink channel directed to the same user is in operation. If the downlink channel is not operating, the TPC control bits may then be used to pass additional pilot bits instead th.

The Rate Information (RI) field is used to send to the sender the possibility provide its data rate without the need for explicit negotiate the instantaneous data rate with the base station, to change. The service field provides information about the particular service for which the data bits are to be used. The length field specifies the length of time of the package. The signal field can be used to add an extra Control information, if needed provide.

additional functionalities of the common packet channel are: (1) Bandwidth Management and (2) L2 receiving confirmation mechanism.

The Bandwidth management functionality is via signaling information implemented on the common control channel in the downlink. It There are three ways to incorporate this functionality. The first is based on a change in the priority status from all uplink users, which currently send information using the CPCH. Through this process, all users enter their priority status Control signal sent on the downlink. If the priority As the CPCH user is reduced, their ability to do so becomes an uplink channel to obtain reduced. Thus, the amount of data which through on the uplink the CPCH users are sent reduced. The further mechanism This is because the base station forwards the maximum possible data rate, which CPCH users for transmission is allowed. This prevents the CPCH users from having a rate which, possibly exceed the uplink system capacity can, and therefore degrades the cell, that is the communication for all users, which are currently connected to the base station interrupts. For the third method, the base station can receive a negative acknowledgment provide the ACK signal. In this case any remote station will be tuned to it is to receive the ACK signal on another transmission from an access burst signal prevented.

Of the L2 receiving confirmation (L2 ACK) mechanism, which is different from the L1 ACK used by the base station to the remote station Correctness of an upward to report route packet reception. The base station can either forward to the remote station which sections of the package received correctly, or which were received incorrectly. There are many existing ways to implement a given one Protocol to forward this type of information. For example, can the packet can be identified such that it has a number of frames contains each frame containing a number of subframes. The Frames are identified by a predetermined number. The Subframes in each frame are also defined by a specific Number identified. A way for the base station for information about the correctness of the package to forward, lies in the identification of all frames and subframes, which received correctly. Another way is identification the frame and subframe which were received incorrectly. The way to make the base station the correctness of a frame or subframe, is in the review of his cyclic remainder code (Cyclic Residue Code, CRC) field. There may be other, more robust mechanisms for confirmation of receipt be used. For example, a negative acknowledgment may be a part of it be the common packet channel. The base station can be a negative Acknowledgment of receipt (ACK), as part of the L1 ACK send to the remote station for a transmission of the message part.

CD mode

There are many remote stations that can try to access the base station at the same time. There are a number of different preamble signals that a remote station can use to reach the base station. each remote station randomly selects one of the preamble signals for use in accessing the base station. The base station transmits a broadcast channel with common synchronization. This broadcast channel with common synchronization contains a frame timing signal. The remote stations extract the frame timing sent by the base station by receiving the broadcast channel with common synchronization. The frame timing is used by the remote stations to obtain a timing plan by dividing the frame duration into a number of access slots. The remote stations are allowed to send their preambles only at the beginning of each access slot. The actual transmission times for different remote stations may differ slightly due to their different propagation delays. This determines an access protocol, commonly known as the slotted ALOHA access protocol. Each remote station repeatedly transmits its preamble signal until the base station detects the preamble acknowledgments that the preamble is received, and the acknowledgment is received correctly by the remote station. There may be more than one remote station which transmits the same preamble signal in the same access slot. The base station can not detect if two or more remote stations are transmitting the same preamble in the same access slot. When the base station detects the transmission of a preamble signal, it transmits an acknowledgment message. There is an acknowledgment message corresponding to each possible preamble signal. Thus, there are as many acknowledgment messages as there are preamble signals. Each transmitting remote station receiving an acknowledgment message corresponding to its transmitting preamble signal will begin transmission of its message. For each preamble signal there is a corresponding spreading code which is used by the base station to send the message. The message transmission always begins at the beginning of an access slot. Since there may be a number of remote stations that use the same preamble signal in the same access slot, they can begin transmitting their message at the same time using the same spreading code. In this case, the transmissions of the remote stations are likely to interfere with each other and thus will not be received correctly.

each Remote station contains a collision detection (CD) field at the beginning of the sent message. The CD field becomes random through each remote station and independently of each other remote station selected. There are a predetermined limited number of CD fields. Two Remote stations sending their message at the same time choose most likely a different CD field. If the base station is the CD field receives the base station will reflect the CD field to the remote station, or return. The remote station reads the reflected CD field through the base station out. When the reflected CD field coincides with the CD field, which the remote station has sent, the remote station assumes that the remote station correctly received by the base station, and continues with a transmission from the rest of the message or data. If that reflected CD field from the base station does not match the one sent by the remote station, then the remote station assumes that there was a collision, and ends a transmission the remaining message or the data.

Before data power control

12 shows an alternative embodiment for the RS access burst signal sent from the remote station to the base station. The base station transmits a frame timing signal which uses the broadcast channel with common synchronization. The remote station synchronizes to the broadcast channel with common synchronization and obtains frame timing information from the frame timing signal. The frame timing information includes the timing of when the remote station can send an access burst signal. Using the frame timing information, the remote station establishes a transmission timing plan. In this embodiment, the remote station divides the frame period into a number of access time slots. The duration of a timeslot may be half the duration of an access slot. The remote station starts sending an access burst signal at the beginning of an access time slot. The frame time reference of the remote station is not necessarily equal to the frame time reference from the base station due to propagation delays.

The access burst signal from 12 Each includes a plurality of RS preamble signals, RS power control signals, and RS pilot signals, which are transmitted at the right time at increasing power levels. The power of RS preamble signal to RS preamble signal increases in accordance with the power values P ₀ , P ₁ , P ₂ , .... The power values increase according to their index, that is, P ₀ <P ₁ <P ₂ , .... The combined plurality of RS preamble signals, RS power control signals, and RS pilot signals compose some or all of the access burst signal , The power level of the RS power control signal and the RS pilot signal may be proportional to the power level of the RS preamble signal.

The A plurality of RS preamble signals, RS power control signals, and RS pilot signals are followed in time by data. Thus, can the access push signal also contain a data part. Alternatively, the access push signal the plurality of RS preamble signals, RS power control signals, and Contain RS pilot signals, and the data is considered to be with the access burst signal connected considered. The data can a message information or other information, such as Signaling, etc. included. The data are preferably linked to, or part of, the access burst signal, however, may be separate from the access burst signal be sent.

As in 12 First, an RS power control signal is sent in time during the time interval between the RS preamble signals. The RS preamble signal is a period of access burst Nalles. Second, an RS pilot signal is sent in time between the RS preamble signal to the RS preamble signal during the time interval.

The RS power control signal is used to control the power of a allocated downlink channel. The base station transmits the assigned one downlink in response to the detection of the RS preamble signal, which from the remote station is sent. The RS pilot signal allows the base station, the received power from the remote station, and thus a power control the remote station, using power control information which from the base station to the remote station is sent to measure.

Within an access burst signal, the remote station continuously transmits an RS preamble signal, followed by an RS power control signal, and followed by an RS pilot signal. The base station receiver searches for transmission of the RS preamble signals. At a predetermined time, immediately after the base station detects an RS preamble signal, the base station begins to transmit an RS preamble signal, as in FIG 12 shown. The remote station tunes its receiver after each transmission of an RS preamble signal to receive the BS preamble pilot signal. The RS pilot signal transmission clock offset is previously known to the remote station. The remote station begins receiving the RS preamble pilot signal immediately at the known time. The spreading code used by the base station to transmit the BS preamble pilot signal is known to the remote station because the BS preamble pilot signal is associated with the type of RS preamble signal which is the remote Station transmits.

The Remote station starts the reception process of the BS preamble pilot signal, whether the BS preamble pilot signal is sent or not sent is. The remote station does not make any effort to determine if the BS preamble pilot signal was sent or not. The reception of the BS preamble pilot signal makes it possible the remote station, the signal quality of the transmitted BS preamble pilot signal to eat. This quality measurement For example, the received signal-to-noise ratio (SNR) or a probability of error due to the reception of the BS preamble pilot signal be through the remote station.

Of the initial Power level of the BS preamble pilot signal is through the base station before transmission certainly. As a result of receipt of the BS preamble pilot signal the remote station, whether the SNR of the received BS preamble pilot signal above or below a previously determined SNR level of the remote station (RS-SNR level). If the BS preamble pilot signal is not sent by the base station, the remote station becomes demodulator or processor is likely to then decide that the transmitted BS preamble pilot signal is received at a SNR which is very well below the predetermined one RS-SNR level is.

While that received SNR of the BS preamble pilot signal measured the remote station sends power control commands below Use of the RS power control signal. When the SNR of the received BS preamble pilot signal, which measured by the remote station, below the previously determined RS-SNR level drops, the remote station then sends an "increase" signal, for example a 1-bit the base station requesting the base station transmits the transmission power level of the BS preamble pilot signal. In case the SNR of the BS preamble pilot signal transmitted by the remote station is measured above the previously determined RS-SNR level, transmits the remote station a "reduce" signal, for example a 0-bit, to the base station requesting the base station, the transmission power level of the BS preamble pilot signal to reduce. This process continues for the duration of the RS power control signal continued. When the base station receives the RS preamble signal then the power of the transmitted BS preamble pilot signal is then passed through the remote station is set to receive the measured SNR of the received BS preamble pilot near the predetermined RS-SNR level.

After a predetermined time interval from the detection of the RS preamble signal, the base station transmits an acknowledgment message. The time of transmission as well as the code structure of the acknowledgment message are known to the remote station. The structure of the acknowledgment message is associated with the code structure of the RS preamble sent by the remote station. The remote station tunes in its receiver to detect the acknowledgment message. At the same time, the remote station starts to transmit the RS pilot signal whose reception by the base station is possible because the base station knows the transmission time as well as the code structure of the RS pilot signal. If the remote station does not work When an acknowledgment sent by the base station is detected, the remote station then assumes that the RS preamble signal previously transmitted by the remote station is not detected by the base station. In such case, the remote station will stop transmitting the next RS preamble signal transmission. When the remote station detects the transmission of the acknowledgment message, the remote station will then decode the message.

Based the decoded message, the remote station decides whether the decoded Acknowledgment message is a positive or negative acknowledgment. If the receipt confirmation message is determined to be negative, then the remote station becomes any transmissions break up. The remote station will start again at a later time, by going to a predetermined reset process. If the Acknowledgment message is determined to be positive, the remote station is having a transmission continue the RS pilot signal.

The Base station receives the RS pilot signal and determines whether the received SNR of the received RS pilot signal is above or below a predetermined BS SNR level. If that measured received SNR of the RS pilot signal below the predetermined one BS-SNR level, then the base station commands the remote station, the transmission power from the remote station to increase, by a "raise" signal, such as a 1-bit command sent to the remote station. If that measured received SNR of the RS pilot signal above the predetermined one BS SNR level, the base station then instructs the remote station to transmit decrease by using a "reduce" signal, such as a 0-bit command sent to the remote station. These commands can about a sentence of DPCCH pilot symbols, followed by low power DPCCH power control symbols, be sent.

During the first two time slots, additional power control commands are sent between successive DPCCH power control symbols and DPCCH pilot symbols, as in FIG 12 shown. The transmission of these power control commands brings the power level of the transmitted RS pilot signal near the predetermined BS SNR level. For safety's sake, the total amount of power change for both the remote station and the base station can be limited to a predetermined maximum value. This value can be fixed or sent out by the base station. Since the remote station has received a positive acknowledgment from the base station and the remote station has completed the transmission of the RS pilot signal, the remote station transmits an RS collision detection field which is followed by a message indicating data information wearing. The RS collision detection field is received by the base station and sent back to the remote station as a BS collision detection field on the following transmitted time slot. If the BS collision detection field received by the remote station matches the RS collision detection field transmitted by the remote station, then the remote station continues to transmit the remaining message.

The Base station is running Continue with a power control of the remote station by continuously DPDCH pilot signals and DPDCH power control signals sent become. If the BS collision detection field does not match the sent RS collision detection field, the remote station then decides that its transmission is with the transmission collided by another remote station, which is the same Time is trying to access the base station by the same RS-access-burst signal Code structure is used and terminates any transmission to a later Time.

CPCH with ping-pong preamble

Usually locates the remote station before entering transmission mode Base stations in their immediate neighborhood and decide to send to the base station with the strongest reception. The Selection of which base station to send is a remote station transmission decision. The decision is based on the received power or equivalent on the error probability by the remote station of the Base stations. Most of the time, the remote station transmission will be a notable one Receive power from only a single base station. In In this case, the remote station needs only this base station to communicate.

An estimate of the power at which a base station receives a remote station may be generated based on the amount of power that the remote station receives the base station. This is usually called an idle power estimate. The idle power estimate allows a remote station to determine the power received at different base stations by the amount of power with which the remote station receives those base stations. Provided that the uplink and downlink frequencies are different, this is one not very accurate estimate. However, this idle power estimate may be used to determine if one or more base stations are candidates for communication. This may be particularly useful if the remote station is located on the outside of a cell. In this case, remote station transmission from more than a single base station can be strongly received. A more important measurement is the performance by which the remote station is received by the base stations. This is because when the common packet channel is operated, much of the uplink information transmission is. In this embodiment, an alternative to the previous CPCH concept, which allows the remote station the longest time, selects the best-received base station. The alternative provides a significant capacity advantage to remote stations operating on the outside of a cell. Connecting to the base station which most strongly receives the remote stations maximizes overall system capacity.

If the remote station has a specific base station for communication selects and establishes a communication with the selected base station, the remote station is then connected to this base station.

One Way at which the remote station (RS) can select which base station she should connect to is in the transmission an RS preamble to more than one base station, and then a selection of either the base station receiving approved or with the base station that receives the most when more than one base station the reception to about confirmed at the same time.

Usually There are different RS preambles for each base station. Also, provided that the base stations are not synchronized, can transmissions to different base stations at different times occur. Therefore, the remote station must alternatively connect to a number of base stations send and also their receipts to different Expect times. Obviously, the remote station transmits to a single base station and always the same RS preamble when the remote station considers it within the reception area of only a single base station.

It is assumed that the remote station is within the reception range of two base stations. As based on 13 The remote station transmits sequentially two different preambles to two base stations. These are two RS signal preambles. The power of the signal preambles increases with time. The preamble for the first base station, namely base station 0, as indicated by the second index, is transmitted at powers P _0,0 , P _1,0 , P _2,0 .... The preamble for the second base station, namely base station 1 as indicated by the second index, is transmitted at powers P _0,1 , P _1,1 , P _2,1 .... In this case, only the first base station acknowledges receipt of the second RS preamble. The remote station then performs the collision detection / collision resolution (CD / CR) process, the RS-CLPC preamble transmission, and the transmission of the data information. Ways to allow preamble transmissions to more than two base stations may be derived from the above procedure. From 13 For example, it is assumed that the reception of the last RS preamble in the first base station is received more than the last RS preamble at the second base station. Therefore, the base station having the better uplink channel is selected. A remote station may also have the option of responding to the first base station, which acknowledges preamble reception. This may be the case when the information transfer delay needs to be minimized.

In 14 Both the first base station and the second base station acknowledge their respective RS preamble reception. However, the remote station performs the CD / CR process for the first base station without waiting for receipt of the acknowledgment from the second base station. The remaining process is the same as before, with the remote station in communication with the first base station.

In 15 the remote station waits for the possible receipt of both acknowledgments before deciding to which base station the CD / CR preamble signal will be sent. This allows the remote station to select the base station that is receiving the most. This does not necessarily guarantee that the selected base station is the one with the better uplink channel. Statistically, however, the base station most strongly received by the remote station is most likely to have the better uplink channel.

CPCH operation using a common preamble

If the remote station is in an area about the same distance to two or more base stations, then the performance is wel At the remote station, reception from the base stations does not give a clear indication of which base station the remote station best receives. A mechanism is needed so that the received base station is used for communication most of the time.

In Certain cases For example, the remote station can send an RS preamble, which is two or several base stations in common. The two or more Base stations form a base station group. The common RS preamble is used by all base stations in the base station group receive. The base stations that form the base station group become decided by the remote station by the performance readouts or equivalent error probability readings from base station receipts within the reception range (RR) used by the remote station become.

In front the shock transmission choose the Remote station is the group of base stations which are considered potential Base stations are considered, with which built a route becomes. The information about which base stations belong to the base station group for each remote station will be preceeded through a prior communication between the remote station and a base station forwarded in the immediate vicinity of the remote station. This base station should also be a member of the selected base station group be. At the origin of the transmission from the remote station will be all Base stations in the base station group tuned to this receive common RS preamble. At a certain Point will be one or more base stations from the base station group the RS signal preamble capture and over theirs Downlink channel an L1 acknowledgment (L1 ACK).

As in 16 As shown, two base stations from the base station group acknowledge the common RS preamble transmission. The remote station, knowing the timing of the L1 acknowledgment for all base stations in the base station group, can determine if and how many base stations are acknowledged. When the relative powers of the L1 acknowledgment signals are measured, the remote station then sends a collision detection / collision resolution (CD / CR) preamble to a single base station. That is, the remote station sends a CD / CR preamble which can be detected by the selected base station in the base station group. The base station receiving the CD / CR preamble returns with the same CD / CR preamble. The different CD / CR preamble code structures are known to all base stations in the base station group by a particular agreement previously made between the remote station and the base stations in the base station group. The CD / CR preamble is for the purpose of detecting the likelihood of more than a single transmission of a common RS preamble from different remote stations.

With the remote station, which happens to be a CD / CR preamble from a set of possible ones Selecting CD / CR preambles will be until the same CD / CR preambles of the selected one Base station are reflected back, the remote station at least temporarily refrain from their imaginary transmission to complete. At a predetermined time instant both the remote station as well as the selected base station a transmission processor-coupled power control preambles (CLPC preambles) kick off. The base station sends a BS-CLPC preamble, and the remote station sends an RS-CLPC preamble. The Signal preambles are used for processor-coupled power control from both the remote station and the base station prior to transmission from the current information and the control data.

It It will be apparent to those skilled in the art that various modifications are made the common packet channel of the present invention are made can, without departing from the scope of the invention and it is intended that the present invention modifications and variations of the common Packing channels, provided that they are within the scope the appended claims come.

Claims (16)

Method for transmitting data for one of several base stations BS ( 31 - 33 A wireless CDMA telecommunication network, the base station comprising a BS spread spectrum transmitter and a BS spread spectrum receiver, the method comprising the steps of: transmitting a frame timing signal from the BS spread spectrum transmitter over a broadcast channel in common synchronization with a common chip sequence signal; At least one segment of an access burst signal comprising a preamble of sufficient power level from a remote station ( 35 ) is received at the BS spread-spectrum receiver at a detected power level, the access burst signal comprising a plurality of segments each because a particular preamble comprises a set of preamble preambles and a pilot signal such that the segments are transmitted at incrementally increasing power levels, the access burst signal beginning at the beginning of an access slot as defined by a frame timing derived from the frame timing signal; Sending a receive operation from the BS spread spectrum transmitter to the remote station in response to receipt of the at least one segment of the access burst signal and corresponding to the specific preamble structure received by the base station; From the remote station, a selected collision detection code (CD code) of a plurality of such codes is received by the BS spread spectrum receiver; From the BS spread spectrum transmitter, a BS-CD code corresponding to the received CD-code is sent to the remote station; and receiving a spread spectrum signal from the remote station at the BS spread spectrum receiver, the spread spectrum signal comprising any data and power control information. The method of claim 1, wherein the pilot signal is eliminated by setting it to a zero power level. A method according to claim 1 or 2, wherein simultaneously with the reception of the spread spectrum signal from the remote station any data and power control information from the BS spread spectrum transmitter be sent. The method of claim 3, wherein transmitting any Data and power control information from the BS spread spectrum transmitter at power levels that takes place from the remote station received power control information based. Method according to claim 3 or 4, wherein the transmission any data and power control information from the BS spread spectrum transmitter begins with sending a first power control information, followed by any data and power control information. Wireless Code Division Multiple Access (CDMA) Base Station BS ( 31 - 33 ) comprising a BS spread spectrum transmitter and a BS spread spectrum receiver and a control unit, characterized in that in operation the CDMA base station is adapted to perform the steps of: transmitting a frame timing signal from the BS spread spectrum transmitter over a broadcast channel with common synchronization with a common chip sequence signal; At least one segment of an access burst signal comprising a preamble of sufficient power level from a remote station ( 35 ) is received at the BS spread-spectrum receiver at a detected power level, the access burst signal comprising a plurality of segments each comprising a particular preamble of a set of preamble preambles and a pilot signal such that the segments are transmitted at incrementally sequentially increasing power levels An access burst signal at the beginning of an access slot, as defined by a frame timing derived from the frame timing signal; Sending a receive operation from the BS spread spectrum transmitter to the remote station in response to receipt of the at least one segment of the access burst signal and corresponding to the specific preamble structure received by the base station; and receiving a spread spectrum signal from the remote station at the BS spread spectrum receiver, the spread spectrum signal comprising any data and power control information. The base station of claim 6, wherein the pilot signal is eliminated by setting it to a zero power level. A base station as claimed in claim 6 or 7, wherein the BS spread spectrum transmitter is arranged to simultaneously with the reception of data transmission from the remote station ( 35 ) to send any data and power control information. The base station of claim 8, wherein the BS spread spectrum transmitter is designed to provide any data and power control information at power levels received by the remote station Power control information based. A base station according to claim 8 or 9, wherein the BS spread spectrum transmitter is designed to provide any data and power control information what to do with sending a first power control information begins, followed by any data and power control information. Processing unit of a wireless code division multiple access (CDMA) base station BS ( 31 - 33 ), Comprising: - a signal tag processor ( 316 ) to detect a preamble in received spread spectrum signals; A data and control processor ( 318 ) to detect data and control information contained in the received spread spectrum signals sen and process; An encoder ( 322 ) for encoding data; An interleaving unit coupled to the coder ( 323 ) to interleave coded data; A packet formatter coupled to the interleaving unit ( 324 ) to format any interleaved coded data, signaling, acknowledgment signal, collision detection signal, pilot signal, and transmission power control (TPC) signal into a packet; and a control unit ( 319 ) coupled to the signal tag processor, the data and control processor, and the packet formatter for controlling the signal tag processor such that, in operation, the processing unit is configured to perform the steps of: detecting a coded preamble of an access strobe signal that is a first embedded at a corresponding power level spread spectrum signal, the access burst signal comprising a plurality of segments each comprising a particular preamble of a set of preamble preambles such that the segments are transmitted at incrementally sequentially increasing power levels, - generating a packet comprising an acknowledgment signal upon detection of the coded preamble signal at the corresponding power level, and outputting the packet comprising the acknowledgment signal to a modulator of the wireless base station, Detecting a collision detection code in a second spread spectrum signal received at the wireless base station; Generating a packet comprising a base station collision detection code coincident with the received collision detection code, and outputting the packet comprising the base station collision detection code to the wireless base station modulator, and generating a packet comprising any data and control information, and Outputting the packet to the modulator of the wireless base station. Processing unit according to claim 11, in addition a programmable adaptation filter ( 315 ) to focus the received spread spectrum signals. Processing unit according to claim 11, beyond a correlator comprising the received spread spectrum signals to bundle. Processing unit according to claim 11, further comprising: - an A / D converter ( 314 ) for converting the spread spectrum signals received from an antenna into a digital signal; and means responsive to the digital signal from the A / D converter to combine the received spread spectrum signals. Processing unit according to claim 11 or 14, further comprising: - a device ( 326 ) for processing the packages for their distribution; and a D / A converter ( 328 ) coupled to the means for processing to generate a modulated spread-spectrum signal for transmission from the base station, the means for processing and the D / A converters forming at least part of the wireless base station modulator. Processing unit according to claim 11, further comprising a building block ( 325 variable gain encoder coupled to the packet formatter to adjust the level of packets from the packet formatter before being applied to the wireless base station modulator.